Problem: Solve for $x$ : $16 = x - 24$
Solution: Add $24$ to both sides: $ \begin{eqnarray} \\ \hphantom{16 {+ 24}} &\hphantom{=}& \hphantom{x} \\ 16 &=& x - 24 \\ \\ {+24} && {+24} \\ \end{eqnarray} $ $ \begin{eqnarray} \\ 16 {+ 24} &=& x \\ \end{eqnarray} $ Simplify. $ x = 40$